Recent Accounting Pronouncements - Additional Information (Details) - USD ($) $ in Millions	12 Months Ended
	Jul. 03, 2020	Jun. 29, 2019	Jun. 28, 2019	Jun. 29, 2018	Jun. 30, 2017
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Increase in lease assets	$ 230
Increase in lease liabilities	245
Cumulative adjustment to retained earnings	$ 9,551		$ 9,967	$ 11,531	$ 11,418
Accounting Standards Update [Extensible List]	us-gaap:AccountingStandardsUpdate201602Member
Change in Accounting Principle, Accounting Standards Update, Transition Option Elected [Extensible List]	wdc:AccountingStandardsUpdate201602ProspectiveMember
Cumulative Effect, Period of Adoption, Adjustment
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cumulative adjustment to retained earnings			(5)	56	51
Retained Earnings
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cumulative adjustment to retained earnings	$ 6,725		7,449	8,757	8,633
Retained Earnings | Cumulative Effect, Period of Adoption, Adjustment
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cumulative adjustment to retained earnings			$ (5)	$ 56	$ 70
Accounting Standards Update 2016-02
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Increase in lease assets		$ 221
Increase in lease liabilities		221
Accounting Standards Update 2016-02 | Retained Earnings | Cumulative Effect, Period of Adoption, Adjustment
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cumulative adjustment to retained earnings		$ (5)